📋 Case Study

Urban Transit Station Gravity Wall Construction

Limited right-of-way requiring 6.2 m tall wall with adjacent historic building (1.2 m clearance)

🏗️ Project Overview

Downtown light rail station, Portland, OR

🎯 Challenge

Limited right-of-way requiring 6.2 m tall wall with adjacent historic building (1.2 m clearance)

🔧 Design Approach

Segmental precast concrete gravity wall with stepped footing and load-spreading granular fill

📐 Design Diagram

_max = 192 kPa S = 8.3 mm Load Path Urban Transit Station Gravity Wall Gravity Wall & Footing Granular Fill Historic Building

AI-generated project design illustration

📐 Key Calculations

Bearing Pressure Redistribution

q_max = (P/A) + (6·M)/(B²)

Result: 192 kPa

Below allowable 200 kPa despite eccentricity

Settlement Prediction

S = C_c/(1+e₀)·H·log(σ'ₚ/σ'₀)

Result: 8.3 mm

Within tolerance for adjacent masonry

📊 Results

Completed in 11 weeks with zero vibration impact on heritage structure; certified by third-party structural monitor

💡 Lessons Learned

• •Precast modularity enables tight urban sequencing
• •Granular fill compaction must exceed 95% Proctor to prevent differential settlement

✅ Key Takeaways

• 1Precast modularity enables tight urban sequencing
• 2Granular fill compaction must exceed 95% Proctor to prevent differential settlement